diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 79c4ad43f..88af3836d 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -191,6 +191,45 @@ jobs:
         if: matrix.platform == 'windows-latest'
         run: .\build.bat test python
 
+  # Native/Rust-extension unit tests for the published fable-library package.
+  # These live in src/fable-library-py/tests and exercise hand-written sources
+  # (fable_library.core, .union, .util) only, so no F# transpilation is needed.
+  # Previously this ran in publish-pypi.yml, where a failure was only visible
+  # at release time and did not actually gate the publish.
+  test-fable-library-py:
+    timeout-minutes: 30
+    strategy:
+      fail-fast: false
+      matrix:
+        platform: [ubuntu-latest, windows-latest, macos-latest]
+        python-version: ["3.12", "3.13", "3.14"]
+    runs-on: ${{ matrix.platform }}
+    env:
+      UV_LINK_MODE: copy
+
+    steps:
+      - uses: actions/checkout@v7
+
+      - name: Set up Python ${{ matrix.python-version }}
+        uses: actions/setup-python@v6
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install Rust
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Set up uv
+        uses: astral-sh/setup-uv@v7
+        with:
+          enable-cache: true
+
+      - name: Build extension and run tests
+        working-directory: ./src/fable-library-py
+        run: |
+          uv sync --frozen
+          uv run --frozen maturin develop --release
+          uv run --frozen pytest tests
+
   # Separate build job for Rust (will run in parallel)
   build-rust:
     timeout-minutes: 75
diff --git a/.github/workflows/publish-pypi.yml b/.github/workflows/publish-pypi.yml
index 5504c5af4..18c3c5b8c 100644
--- a/.github/workflows/publish-pypi.yml
+++ b/.github/workflows/publish-pypi.yml
@@ -57,43 +57,10 @@ jobs:
           path: ./temp/fable-library-py
           retention-days: 1
 
-    test:
-      needs: build-fable-library
-      runs-on: ${{ matrix.os }}
-      timeout-minutes: 30
-      strategy:
-        matrix:
-          os: [ubuntu-latest, windows-latest, macos-latest]
-          python-version: ["3.12", "3.13", "3.14"]
-      env:
-        UV_LINK_MODE: copy
-
-      steps:
-        - uses: actions/checkout@v7
-        - name: Set up Python ${{ matrix.python-version }}
-          uses: actions/setup-python@v6
-          with:
-            python-version: ${{ matrix.python-version }}
-        - name: Install Rust
-          uses: dtolnay/rust-toolchain@stable
-        - name: Install uv
-          uses: astral-sh/setup-uv@v8.2.0
-        - name: Download fable-library-py
-          uses: actions/download-artifact@v8
-          with:
-            name: fable-library-py
-            path: ./src/fable-library-py
-        - name: Build and install
-          uses: PyO3/maturin-action@v1
-          with:
-            working-directory: ./src/fable-library-py
-            args: --release --features=pyo3/extension-module
-        - name: Test
-          run: |
-            cd src/fable-library-py
-            uv sync
-            uv run maturin develop --release
-            uv run pytest tests
+    # NOTE: the fable-library-py native test suite (src/fable-library-py/tests)
+    # runs in build.yml on every push/PR to main. It used to run here too, but
+    # it was never in `release`'s `needs`, so it gated nothing and only
+    # consumed runners the wheel jobs were queuing behind.
 
     linux:
       needs: build-fable-library